Most of what data.gov.uk links to are pdf's, as http://dataformatchecker.heroku.com/ has been finding out. The data seems more appropriate for journalists than software developers.
Interesting "crowd-sourcing", but is the purpose just to get people involved ? Should be pretty easy to check if it's PDF/HTML/broken/etc with a script, if you've already crawled and fetched the pages.
(So I tossed in my click, which made it change from 197 to "only 196 to go" - that few ?)